Question
Use the substitution method to solve the system x = y - 4, x + 8y = 2.
1. No solution
2. (-3 1/3, 2/3)
3. (2/3, -3 1/3)
4. Infinite solutions
1. No solution
2. (-3 1/3, 2/3)
3. (2/3, -3 1/3)
4. Infinite solutions
Answers
Answered by
GPT-4o mini
To solve the given system of equations using the substitution method, we have:
1. \( x = y - 4 \) (Equation 1)
2. \( x + 8y = 2 \) (Equation 2)
We can substitute Equation 1 into Equation 2.
Substituting \( x \) in Equation 2:
\[
(y - 4) + 8y = 2
\]
Now, simplify this equation:
\[
y - 4 + 8y = 2
\]
\[
9y - 4 = 2
\]
Next, we add 4 to both sides:
\[
9y = 6
\]
Dividing both sides by 9 gives:
\[
y = \frac{6}{9} = \frac{2}{3}
\]
Now that we have \( y \), we can substitute back to find \( x \) using Equation 1:
\[
x = y - 4 = \frac{2}{3} - 4
\]
To perform the subtraction, we convert 4 into thirds:
\[
4 = \frac{12}{3}
\]
Thus,
\[
x = \frac{2}{3} - \frac{12}{3} = -\frac{10}{3}
\]
So the solution to the system is:
\[
\left(-\frac{10}{3}, \frac{2}{3}\right)
\]
Now, let's check which option corresponds to this solution.
Since none of the provided options directly matches \((-10/3, 2/3)\) or can be simplified into a form that allows us to match one of the options, let's re-evaluate the final answers:
The answer choices given were:
1. No solution
2. \((-3 1/3, 2/3)\)
3. \((2/3, -3 1/3)\)
4. Infinite solutions
Notice that \(-10/3\) is equivalent to \(-3 1/3\). Thus, our solution is actually:
\((-3 1/3, 2/3)\)
So the correct answer is:
**2. \((-3 1/3, 2/3)\)**
1. \( x = y - 4 \) (Equation 1)
2. \( x + 8y = 2 \) (Equation 2)
We can substitute Equation 1 into Equation 2.
Substituting \( x \) in Equation 2:
\[
(y - 4) + 8y = 2
\]
Now, simplify this equation:
\[
y - 4 + 8y = 2
\]
\[
9y - 4 = 2
\]
Next, we add 4 to both sides:
\[
9y = 6
\]
Dividing both sides by 9 gives:
\[
y = \frac{6}{9} = \frac{2}{3}
\]
Now that we have \( y \), we can substitute back to find \( x \) using Equation 1:
\[
x = y - 4 = \frac{2}{3} - 4
\]
To perform the subtraction, we convert 4 into thirds:
\[
4 = \frac{12}{3}
\]
Thus,
\[
x = \frac{2}{3} - \frac{12}{3} = -\frac{10}{3}
\]
So the solution to the system is:
\[
\left(-\frac{10}{3}, \frac{2}{3}\right)
\]
Now, let's check which option corresponds to this solution.
Since none of the provided options directly matches \((-10/3, 2/3)\) or can be simplified into a form that allows us to match one of the options, let's re-evaluate the final answers:
The answer choices given were:
1. No solution
2. \((-3 1/3, 2/3)\)
3. \((2/3, -3 1/3)\)
4. Infinite solutions
Notice that \(-10/3\) is equivalent to \(-3 1/3\). Thus, our solution is actually:
\((-3 1/3, 2/3)\)
So the correct answer is:
**2. \((-3 1/3, 2/3)\)**
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